The invention relates generally to the electrical interconnection of angularly disposed surfaces that each include one or more conductive patterns. Specifically, the invention relates to a simple and cost-effective method for interconnecting angularly disposed electrical contacts, also referred to herein as conductive patterns, such as the interconnection of a three-dimensional, multi-layer electronic module to a printed circuit board. The invention also claims a cornerbond assembly that incorporates the method.
There is a continuing demand for higher circuit density in a wide variety of electronic applications such as consumer electronics, space hardware, and military weaponry and hardware. To avoid the two-dimensional limitations of conventional printed circuit boards, industry has begun using high density, three-dimensional, multilayer modules comprised of individual interconnected layers of microelectronic circuitry which occupy very little surface area but provide greatly increased circuit density per given area.
Examples of such three-dimensional modules include those disclosed in U.S. Pat. No. 4,403,238, U.S. Pat. No. 4,525,921, U.S. Pat. No. 5,701,233, U.S. Pat. No. 4,617,160, and U.S. Pat. No. 6,072,234, all to common assignee, Irvine Sensors Corp., the assignee of the present application.
Another example of using the Z-axis to increase circuit density is the use of a daughterboard/motherboard configuration where one or more printed circuit boards are interconnected to a motherboard at a perpendicular angle.
Required input/output and power/ground interfaces between a multi-layer module or daughterboard and a printed circuit board are presently provided in different formats including ball grid array or wire bond interfaces. Each of these methods is undesirable due to the difficulty, time and expense associated with the design and assembly of such interfaces as well as problems with signal path length and related inductance.
Providing conductive contact pads on the surface of the multilayer module or daughterboard for interconnection with the printed circuit board is desirable due to ease of assembly, reworkability and shorter lead length. Unfortunately, there is presently no simple and efficient method for the interconnection of electronic assemblies with interconnection conductive patterns that lie in a perpendicular plane to each other.
It is therefore an object of the invention to provide a simple, cost-effective and reliable method for the electrical interconnection of perpendicular or angularly disposed conductive patterns using industry standard wire bonding equipment.